Core B (Immunology Core) will provide standardized humoral immune monitoring assay services for evaluating antibody responses elicited by Ad26-Env/Gag/Pol prime, Env gp140 protein boost (Ad26/Env) vaccine regimens in the studies described in this IPCAVD program. Core B leadership will work closely with investigators responsible for the studies described in Project 1 and Project 2 and will participate actively in the scientific mission of the overall IPCAVD program. The primary goal of Core B is to provide the leadership and the technical expertise to ensure that all vaccine-induced humoral responses will be profiled in a standardized fashion and that the IPCAVD leadership is kept abreast of the latest developments in assessing vaccine-induced neutralizing and non-neutralizing humoral immunity, particularly in relation to their ability to prevent viral infection. To accomplish these goals, we propose the following three Specific Aims: Specific Aim 1. To perform standardized neutralizing antibody (NAb) assays in both NHP and humans Specific Aim 2. To perform standardized non-neutralizing antibody assays in both NHP and humans Specific Aim 3. To integrate all antibody data into a Systems Serology profiling approach to define correlates of protective immunity